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  1. #1

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    Experiences with Vitamin C developers please

    I'm currently trying to standardise my workflow around a developer that has an amount of Vitamin C in it. Changing from a 1500 series Jobo tank to an Expert tank and changing from roll to sheet film is seeing a drop in ASA of around 1 stop. Given this developer is giving me really slow results from the film anyway the decrease of another stop or so makes it very, very slow.

    So you should assume same temp, same film type, same dilution, same developing time, same amount of developer and similar agitation (slow hand rotations on roller base in a tempered water bath). I pre-wash and develop in distilled (not demineralised) water.

    The film (FP4) has gone from ASA 40 to ASA 25 or so in the Expert tank. The gradient of the roll of film was 0.47 and the sheet film was 0.3.

    I am wondering if there is a problem with Vit C running out of puff. Does a developer containing Vit C go off any differently than other developers ? Does Vit C tend to react more or less with agitation ? Should I really be using another chemical in the developing fluid - like a preservative of some sort ?

    The developer is essentially 510 Pyro at 1:200 in TEA.

    Having such flukey results means I have no surety in processing at this stage and the terribly slow ASA results are a worry too.

    Cheers,

    Steve

  2. #2

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    Yes ascorbic acid, vitamin C can be subject to the Fenton reaction. This can result in a very rapid loss of developing activity. The reaction is catalyzed by iron and copper ions which can be in the water OR in the chemicals used to compound the developer. Now the TEA will complex copper ions and prevent their action.

    That being said, very dilute developers do not respond well to any agitation method that causes an unusual amount of aeration. So it may be the change in developing tank and its use.

    Another possibility when changing tanks with very dilute developers is the change in the amount of working strength developer per in2 of film. Notice that what is important is not the total volume of developer in each style tank For example, if you have two tanks each with the same amount of developer but one contains more film than the other you may have difficulties. I would suggest a test trying a dilution of 1:100 rather than 1:200.

    I assume that your vit C is fresh and shows no signs of oxidation.
    Last edited by Gerald C Koch; 03-12-2015 at 10:18 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  3. #3

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    Gerald,

    The batch of 510 that I refer to is my second batch. Initially I purchased a special order from the Formulary but it was black when I got it.

    This batch was made by me from all fresh and special order chemicals especially the TEA. It is still a weak straw colour today as I used it. I have just walked back into the room after a development session and I think it is even worse than the other day.

    I did use a metal extension on the syringe to draw the developer into a syringe before using. I do use stainless steel jugs to mix all my chemicals in. A separate jug for each thing; pre-wash, dev, stop, fixer, wash, etc.

    I have done a complete BTZS test with this developer only a month ago and the results were fairly usable at 1:200. The results I have now are shocking. Its as though in the last month or 6 weeks the developer has lost 60-80% of its strength. I was going past 2.4 in density on FP4 ! Now it'd be lucky to hit 1.0.

    As 510 has three developers in it how can a Fenton reaction cause such a loss of activity ? Isn't the loss of one agent just a part of the whole thing ? It seems to me that the whole development process is dead or dying.

    I believe XTOL is also a developer that - at least in the past - died without notice. Doesn't it also have Vit C ?

    I also store all my stock chemicals under nitrogen in amber bottles.

    Steve

  4. #4

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    The Fenton reaction will not effect the phenidone or the pyrogallol which would explain why you are still getting some image. But if you can eliminate all other variables then the problem is with the ascorbic acid.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  5. #5

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    Thanks Gerald,

    I realise there is a superadditive reaction in there also and that might explain the rapid decline. My question is specifically looking at those developers with Vit C ascorbic because I have the Formulary containers of Pyrocat-HD and I swear they are good for 3 years and that is without any nitrogen.

    I'm looking questioningly at the ascorbic vit C as the culprit here and I want to hear of any others who may have this view too.

    Cheers,

    Steve

  6. #6

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    http://unblinkingeye.com/Articles/PCat/PCat2/pcat2.html
    Here Sandy King discusses the oxidation of Pyrogallol in rotary processors and the advantages of pyrocatechin.
    Its not entirely clear that vit C is the cause of the loss of film speed,is there a possibility it may be down to oxidation of pyrogallol?

  7. #7
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    Quote Originally Posted by Gerald C Koch View Post
    Yes ascorbic acid, vitamin C can be subject to the Fenton reaction. This can result in a very rapid loss of developing activity. The reaction is catalyzed by iron and copper ions which can be in the water OR in the chemicals used to compound the developer. Now the TEA will complex copper ions and prevent their action.
    IIRC you need another compound to also sequester iron impurities, Ryuji Suzuki's developers use Salicylic Acid for this purpose, whereas there is no suitable compound in 510 Pyro.

    @swmcl: you can test very easily whether the Ascorbic Acid in your concentrate has gone bad: prepare two standard batches of working solution, to one of which you add 0.5 g/l Ascorbic Acid and 0.5 ml/l TEA. Both compounds can be easily sourced locally. Expose two sheets and develop them one in each soup, if the second one shows normal development whereas the first one looks underdeveloped, you know the Ascorbic Acid in your concentrate has gone bad. In this case you can "repair" your developer (but not the concentrate!) until you have prepared fresh concentrate.
    Trying to be the best of whatever I am, even if what I am is no good.

  8. #8

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    Quote Originally Posted by Rudeofus View Post
    IIRC you need another compound to also sequester iron impurities, Ryuji Suzuki's developers use Salicylic Acid for this purpose, whereas there is no suitable compound in 510 Pyro.
    Due to the choice of chelating agents two were needed in Ryuji's formulas. Remember the requirement that any choice be readily available for the average person. The TEA chelated the copper and the salicylic acid the iron. There are chelating agents that will do both but they are either expensive or hard to obtain.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  9. #9

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    I have also been having trouble with those developers. Very low activity. Maybe the problem is using a jobo at high rotation since the pyro is always very oxidized at the end as mentioned. Also had trouble with PC-TEA and Pyro Uno. I'm wondering if the vit. C is any good - new from Formulary. I made a NaAscorbate developer LSD-6, using and it was very active. However that has sulfite and may be better with a jobo. I think I'll try titrate with iodine to determine if the pyro and vit. C is good, and try in a manual tank.

  10. #10
    Rudeofus's Avatar
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    sfaber17, can you confirm that your Pyro/Ascorbate developers were a lot more dilute than this LSD-6 developer? This may explain quite a bit ...
    Trying to be the best of whatever I am, even if what I am is no good.

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